1. Field of the Invention
An aspect of the present invention relates to an ink jet printer having an improved arrangement of a heater to prevent liquid ink from being solidified.
2. Description of the Related Art
Generally, an ink jet printer is inexpensive, is capable of high-performance printing, and is also advantageous in forming color images. In this respect, the ink jet printer has been widely used. The ink jet printer has a print head device formed with a multiplicity of fine nozzles through which ink is ejected toward paper to form images on the paper.
Generally, there are two kinds of ink jet printers: a liquid ink jet printer and a solid ink jet printer. The liquid ink jet printer stores ink in a liquid state and supplies liquid ink to a print head device, whereas the solid ink jet printer stores ink in a solid state, liquefies solid ink by necessary amounts and supplies the liquefied ink to the print head device. The solid ink jet printer uses solid ink that is mainly made of paraffin, which produces excellent glazed images, has good color sense and a cubic effect; further, generation of waste ink may be reduced. For this reason, the solid ink jet printer is widely used.
FIG. 1 schematically illustrates a conventional ink jet printer. As illustrated, an ink jet printer 100 comprises an ink reservoir 110 and heaters 130 to liquefy remaining ink.
The ink reservoir 110 stores liquid ink produced by heating and melting solid ink that is stored in an ink supplying unit (not shown). An ink accommodating unit 140 accommodates liquid ink from the ink supplying unit (not shown), and an ink passage 145 provides communication between the ink accommodating unit 140 and the ink reservoir 110, to thereby allow liquid ink accommodated in the ink accommodating unit 140 to flow into the ink reservoir 110.
The ink reservoir 110 comprises a supplying pipe 150 to supply ink to a print head 120. The print head 120 receives ink from the ink reservoir 110 through the ink supplying pipe 150, and ejects them onto paper.
The heaters 130 heat liquid ink that is stored in the ink reservoir 110 so as to prevent them from being solidified until they are supplied to the print head 120 through the ink supplying pipe 150. The heaters 130 are supported by an insertion hole 135 formed in a direction that is perpendicular to the lengthwise direction of the ink reservoir 110. This construction of the conventional ink jet printer is disclosed in U.S. Pat. No. 6,003,971.
Usually, a heat transmission rate of the heater 130 depends on a distance between the heater 130 and the liquid ink; that is, the closer the heaters 130 and the liquid ink are to each other, the higher the heat transmission rate between them is. However, as noted above, in the conventional ink jet printer 100, the heaters 130 are arranged in directions that are perpendicular to the lengthwise direction of the ink reservoir 110. Thus, the rate of heat transmission to the liquid ink stored within the ink reservoir 110 is degraded. In other words, since the liquid ink is disposed along the lengthwise direction of the ink reservoir 110 and adapt to the shape of the ink reservoir 110, and since the heaters 130 are arranged perpendicular to the lengthwise direction of the ink reservoir 110, thus, an average separation between the heaters 130 and the liquid ink is distant.
Because of this distant arrangement, only a portion of the liquid ink disposed for the length of the ink reservoir 110 may be heated by the heater 130, thereby degrading the heating rate of the heater 130 to heat liquid ink. In addition, to heat liquid ink stored for the whole length of the ink reservoir 110, a plurality of heaters 130 need to be disposed along the lengthwise direction of the ink reservoir 110.